Until recently, improvements in the standards for passenger vehicle lubricants and commercial vehicle lubricants were achieved largely with the use of better additives, such as anti-oxidants, antiwear agents, detergents and viscosity improvers to improve specific properties of the basestocks used to prepare the finished products. In the 1990s, with the advent of increased environmental concerns, the performance requirements for the basestocks themselves have increased. The performance of the lubricating oil products themselves began a rapid change as additives alone have not been able to address the new requirements demanded by the equipment manufacturers accelerated efforts to improve automotive performance, via reduced emissions and fuel economy, etc. In North America over the past decade SAE 5W-30 oils have required basestock viscosity index (“VI”) of the light basestock to increase from about 100 to 115 due to tougher ILSAC, GF-1, GF 2 and GF3 standards. VI is a convenient guide to low temperature viscosity and volatility, properties that really under pin automotive performance. This VI target is achievable only in low yields, from most crudes, by the conventional separations based, processing steps of vacuum distillation, solvent extraction and solvent dewaxing. Similar trends have occurred in Europe with ACEA requirements.
Conventional techniques for preparing basestocks such as hydrocracking or solvent extraction require severe operating conditions such as high pressure and temperature or high solvent:oil ratios and high extraction temperatures to reach these higher basestock qualities. Either alternative involves expensive operating conditions and low yields.
Further, most lubricating oil feedstocks must be dewaxed in order to produce lubricating oils which will remain fluid down to the lowest temperature of use. Dewaxing is the process of separating or converting hydrocarbons which solidify readily (i.e., waxes) in petroleum fractions. The hydrodewaxing of wax and waxy feeds boiling in the lubricating oil range and catalysts useful in such processes is well known in the art. Generally these processes utilize catalysts comprising a molecular sieve component and a component selected from the Group VIII and/or Group VIB metals.
As finished oil performance requirements increase so does the requirement for improved lube oil basestocks properties. To address this need the search for new and different processes, catalysts and catalyst systems that exhibit improved activity, selectivity and/or longevity is an ongoing exercise. Thus, there is a need in the lube oil market to provide processes that can produce lube oil basestocks that meet the demand for better performance, e.g., increased fuel economy and reduced emissions, etc.